Gene expression profiling is a powerful tool to analyze the complexity of cancer biology. Recent methods allow the generation of gene expression profiles for all known genes in the human genome. The genome-wide analysis of the gene expression patterns of neoplastic and normal cells provides insights into: (1) the identification of previously unknown tumor subtypes; (2) the normal cellular counterparts of tumor cells; (3) the identification of cellular pathways that may be affected by malignant transformation; (4) the identification of new diagnostic markers and potential therapeutic targets. This chapter summarizes experimental approaches addressing these goals using examples from studies on B-cell malignancies.
